One click solution to turning a curved line into a straight line and vice versa

One click solution to turning a curved line into a straight line and vice versa - student project

I have been using Illustrator since version 4.5, so most of the pen tool tips I already knew, although things get updated periodically so this class was a good refresher on using the pen tool. The tips I didn't know about were "Working with the new curvature tool" and the "One click solution to turning a curved line into a straight line and vice versa . . . as you're drawing it".

Thanks for the tips!